Gynnya McMillen was discovered unconscious at the Lincoln Village Regional Juvenile Detention Center in Elizabethtown, Ky.

Investigators in Kentucky are probing the death of a 16-year-old African-American girl who died last week in police custody, according to CBS News:

Gynnya McMillen was found unresponsive early in the morning of Jan. 11, at the Lincoln Village Regional Juvenile Detention Center in Elizabethtown, Ky. State and local officials are investigating, but a week after McMillen’s death, officials have released few details in the case.

Hardin County Coroner William Lee, Jr. said in an interview Monday that in an initial autopsy on Jan. 12, he saw no outward signs, such as “visual bruising,” that could conclusively signal a cause of death. Lee also said it was unlikely she had a heart condition.

Lee said the full results wouldn’t be available for weeks, until after pathology tests were done.

The report notes that “on Jan. 15, a person claiming to be Gynnya’s sister created a Facebook page called “Justice for Gynnya McMillen,” where she calls for authorities to release information about the case.

The Facebook post says that Gynnya died in custody of a detention center, but officials have not released details of how she was discovered and said “her autopsy shows no cause of death,” notes the report.